Publications by authors named "Michael J. Welch"

Background: Peanut allergy, for which there are no approved treatment options, affects patients who are at risk for unpredictable and occasionally life-threatening allergic reactions.

Methods: In a phase 3 trial, we screened participants 4 to 55 years of age with peanut allergy for allergic dose-limiting symptoms at a challenge dose of 100 mg or less of peanut protein (approximately one third of a peanut kernel) in a double-blind, placebo-controlled food challenge. Participants with an allergic response were randomly assigned, in a 3:1 ratio, to receive AR101 (a peanut-derived investigational biologic oral immunotherapy drug) or placebo in an escalating-dose program.

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Introduction: Incorrect use of inhaler devices by patients with asthma is common and can adversely affect clinical outcomes. Devices that are straightforward to use are less likely to result in dosing errors and can improve patients' satisfaction with therapy and adherence. A novel dry-powder formulation of the rescue bronchodilator albuterol (salbutamol) administered using a multidose dry-powder inhaler (mDPI; RespiClick™) has recently been approved in the USA.

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Purpose: The purpose of this study was to evaluate the safety, dosimetry, and apparent receptor occupancy (RO) of [(64)Cu]DOTA-patritumab, a radiolabeled monoclonal antibody directed against HER3/ERBB3 in subjects with advanced solid tumors.

Procedures: Dosimetry subjects (n = 5) received [(64)Cu]DOTA-patritumab and underwent positron emission tomography (PET)/X-ray computed tomography (CT) at 3, 24, and 48 h. Evaluable RO subjects (n = 3 out of 6) received [(64)Cu]DOTA-patritumab at day 1 and day 8 (after 9.

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Acute lung injury (ALI) is a complex syndrome with many aetiologies, resulting in the upregulation of inflammatory mediators in the host, followed by dyspnoea, hypoxemia and pulmonary oedema. A central mediator is inducible nitric oxide synthase (iNOS) that drives the production of NO and continued inflammation. Thus, it is useful to have diagnostic and therapeutic agents for targeting iNOS expression.

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Article Synopsis
  • - The National Institute of Standards and Technology (NIST) and the National Institutes of Health (NIH) created the Standard Reference Material (SRM) 1950 to enhance metabolomics research by providing a reliable reference for metabolite concentrations in human plasma.
  • - SRM 1950 reflects the metabolite profile of adult human plasma, with samples obtained from a diverse group of donors to represent the U.S. population's ethnic composition.
  • - This reference material includes around 100 different analytes such as amino acids and clinical markers, and is the first of its kind specifically designed for the broad applications within the diverse field of metabolomics.
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Gold nanoparticles have attracted much interest as a platform for development of multifunctional imaging and therapeutic agents. Multifunctionalized gold nanoparticles are generally constructed by covalent assembly of a gold core with thiolated ligands. In this study, we have assembled multifunctionalized gold nanoparticles in one step by nucleic acid hybridization of ODN (oligodeoxynucleotide)-derivatized gold nanoparticles with a library of pre-functionalized complementary PNAs (peptide nucleic acids).

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Unlabelled: Atherosclerosis is the pathophysiologic process behind lethal cardiovascular diseases. It is a chronic inflammatory progression. Chemokines can strongly affect the initiation and progression of atherosclerosis by controlling the trafficking of inflammatory cells in vivo through interaction with their receptors.

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Purpose: Somatostatin receptors (SSTR) have been reported as promising targets for imaging agents for cancer. Recently, (68)Ga-DOTATOC-based PET imaging has been used successfully for diagnosis and management of SSTR-expressing tumors. The purpose of this study was to evaluate the influence of chelator modifications and charge on (68)Ga-labeled peptide conjugates.

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Unlabelled: The airway provides a direct route for administration of nanoparticles bearing therapeutic or diagnostic payloads to the lung, however optimization of nanoplatforms for intracellular delivery remains challenging. Poly(ethylene glycol) (PEG) surface modification improves systemic performance but less is known about PEGylated nanoparticles administered to the airway. To test this, we generated a library of cationic, shell crosslinked knedel-like nanoparticles (cSCKs), including PEG (1.

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Specific Activity (SA), defined as the amount of radioactivity per unit mass of a compound is arguably one of the most important parameters in radiopharmaceutical development, particularly in quality control of carbon-11 and fluorine-18 labeled compounds. This review article will outline the progression of improvements in SA over the last few decades. The International Symposium of Radiopharmaceutical Chemistry (ISRC/ISRS) abstracts were an excellent source of materials for this review and will be referenced throughout.

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Dual functional hierarchically assembled nanostructures, with two unique functions of carrying therapeutic cargo electrostatically and maintaining radiolabeled imaging agents covalently within separate component building blocks, have been developed via the supramolecular assembly of several spherical cationic shell cross-linked nanoparticles clustered around a central anionic shell cross-linked cylinder. The shells of the cationic nanoparticles and the hydrophobic core domain of the anionic central cylindrical nanostructure of the assemblies were utilized to complex negatively charged nucleic acids (siRNA) and to undergo radiolabeling, respectively, for potential theranostic applications. The assemblies exhibited exceptional cell transfection and radiolabeling efficiencies, providing an overall advantage over the individual components, which could each facilitate only one or the other of the functions.

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Nanoparticles with tunable pharmacokinetics are desirable for various biomedical applications. Poly(ethylene glycol) (PEG) is well-known to create "stealth" effects to stabilize and extend the blood circulation of nanoparticles. In this work, poly(carboxybetaine) (PCB), a new nonfouling polymer material, was incorporated as surface-grafted coatings, conjugated onto degradable shell cross-linked knedel-like nanoparticles (dSCKs) composed of poly(acrylic acid)-based shells and poly(lactic acid) cores, to compare the in vivo pharmacokinetics to their PEG-functionalized analogues.

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Peroxisome proliferator-activated receptor alpha (PPAR-α) is a ligand-activated nuclear receptor transcription factor that regulates the fatty acid β-oxidation. An in vitro assay identified the p-methoxy phenyl ureido thiobutyric acid derivative KSM-01 (IC(50)=0.28±0.

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Interest in using (68)Ga is rapidly increasing for clinical PET applications due to its favorable imaging characteristics and increased accessibility. The focus of this study was to provide our long-term evaluations of the two TiO(2)-based (68)Ge/(68)Ga generators and develop an optimized automation strategy to synthesize [(68)Ga]DOTATOC by using HEPES as a buffer system. This data will be useful in standardizing the evaluation of (68)Ge/(68)Ga generators and automation strategies to comply with regulatory issues for clinical use.

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Introduction: Click labeling using 2-[¹⁸F]fluoroethyl azide has been proven to be promising methods of radiolabeling small molecules and peptides, some of which are undergoing clinical evaluations. However, the previously reported method afforded low yield, poor purities and under desirable reproducibility.

Methods: A vacuum distillation method was used to isolate 2-[¹⁸F]fluoroethyl azide, and the solvent effect of acetonitrile and dimethylformamide (DMF) on the click labeling using Cu(I) from copper sulfate/sodium ascorbate was studied.

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Objectives: To investigate the potential of monoclonal antibody (mAb) RM2 as a ligand for a radioimmunotracer for prostate cancer imaging.

Methods: Labeling was conducted with mAb RM2 and (125)I using the chloramine-T method. The cell study was conducted with PC-3 and LNCaP, which are prostate cancer cell lines, and MCF-7, which is a breast cancer cell line.

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Introduction: Independent measurement of the levels of both the estrogen receptors, ERα and ERβ, in breast cancer could improve prediction of benefit from endocrine therapies. While ERα levels can be measured by positron emission tomography (PET) using 16α-[(18)F]fluoroestradiol (FES), no effective agent for imaging ERβ by PET has yet been reported.

Methods: We have prepared the fluorine-18 labeled form of 8β-(2-fluoroethyl)estradiol (8BFEE(2)), an analog of an ERβ-selective steroidal estrogen, 8β-vinylestradiol; efficient incorporation of fluorine-18 was achieved, but required very vigorous conditions.

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Unlabelled: Estrogen receptor-α (ERα) and progesterone receptor (PR) are expressed in most human breast cancers and are important predictive factors for directing therapy. Because of de novo and acquired resistance to endocrine therapy, there remains a need to identify which ERα-positive (ERα(+))/PR-positive (PR(+)) tumors are most likely to respond. The purpose of this study was to use estrogen- and progestin-based radiopharmaceuticals to image ERα and PR in mouse mammary tumors at baseline and after hormonal therapy and to determine whether changes in these imaging biomarkers can serve as an early predictive indicator of therapeutic response.

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A novel strategy based on metal-free "click" chemistry was developed for the copper-64 radiolabeling of the core in shell-cross-linked nanoparticles (SCK-NPs). Compared with Cu(I)-catalyzed click chemistry, this metal-free strategy provides the following advantages for Cu-64 labeling of the core of SCK-NPs: (1) elimination of copper exchange between nonradioactive Cu in the catalyst and DOTA-chelated Cu-64; (2) elimination of the internal click reactions between the azide and acetylene groups in the same NPs; and (3) increased efficiency of the click reaction because water-soluble Cu(I) does not need to reach the hydrophobic core of the NPs. When 50 mCi Cu-64 was used for the radiolabeling, the specific activity of the radiolabeled product was 975 Ci/μmol at the end of synthesis, which represents the attachment of ca.

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An automated system for the production of high specific activity (64)Cu via the irradiation of electroplated enriched (64)Ni targets has been developed. We have been operating this system continually on a biweekly or weekly basis for more than two years. Since the inception of this automated production system, (October 1, 2008), we have had 145 productions, produced 53562 mCi and shipped out 25629 mCi of this isotope to external users.

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Unlabelled: This first-in-human study was designed to evaluate the safety and dosimetry of the progesterone analog 21-(18)F-fluoro-16α,17α-[(R)-(1'-α-furylmethylidene)dioxy]-19-norpregn-4-ene-3,20-dione ((18)F-FFNP), as well the feasibility of imaging tumor progesterone receptors (PRs) by PET in breast cancer.

Methods: Women with breast cancer underwent PET with (18)F-FFNP. Tumor (18)F-FFNP uptake was assessed semiquantitatively by determining maximum standardized uptake value and tumor-to-normal breast (T/N) activity ratio and by Logan graphical analysis.

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Introduction: Although breast cancers expressing estrogen receptor-α (ERα) and progesterone receptors (PR) are the most common form of mammary malignancy in humans, it has been difficult to develop a suitable mouse model showing similar steroid hormone responsiveness. STAT transcription factors play critical roles in mammary gland tumorigenesis, but the precise role of STAT1 remains unclear. Herein, we show that a subset of human breast cancers display reduced STAT1 expression and that mice lacking STAT1 surprisingly develop ERα+/PR+ mammary tumors.

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Specific activity (SA), defined as the amount of radioactivity per unit mass of a compound, is arguably one of the most important parameters in radiopharmaceutical development, particularly in quality control of carbon-11- and fluorine-18-labeled compounds. This review article will outline the progression of improvements in SA over the last few decades. The International Symposium of Radiopharmaceutical Chemistry abstracts were an excellent source of materials for this review and will be referenced throughout.

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Over the past decade, positron emitter labeled nanoparticles have been widely used in and substantially improved for a range of diagnostic biomedical research. However, given growing interest in personalized medicine and translational research, a major challenge in the field will be to develop disease-specific nanoprobes with facile and robust radiolabeling strategies and that provide imaging stability, enhanced sensitivity for disease early stage detection, optimized in vivo pharmacokinetics for reduced nonspecific organ uptake, and improved targeting for elevated efficacy. This review briefly summarizes the major applications of nanoparticles labeled with positron emitters for cardiovascular imaging, lung diagnosis, and tumor theranostics.

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Unlabelled: Sensitive, specific, and noninvasive detection of angiogenesis would be helpful in discovering new strategies for the treatment of cardiovascular diseases. Recently, we reported the (64)Cu-labeled C-type atrial natriuretic factor (CANF) fragment for detecting the upregulation of natriuretic peptide clearance receptor (NPR-C) with PET on atherosclerosis-like lesions in an animal model. However, it is unknown whether NPR-C is present and overexpressed during angiogenesis.

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